The use of an assembly of disposable pipette tips, a tip holder and a support structure is well known. Typically, a tip holder takes the form of a tray with individual holes for carrying a number of pipette tips, usually ninety-six. The tip holders often come prepackaged with the tips already inserted, but there are also commercially available means of loading loose tips into tip holders. Alternatively, the tips can be manually placed into the holes of a tip holder. Once the tips are loaded into a tip holder, the tip holder is placed over a support structure and the tips, variably with or without the tip holder, are released into the support structure.
The function of the support structure is to provide support during the tip removal process. Typically, the tips are removed when an instrument, either manually or machine operated, is inserted into the larger open top of the tip, and downward pressure is exerted, thus wedging the tip onto the instrument. The tip is then removed from the support structure, used and subsequently discarded.
The support structure acts to provide physical underlying support for this process, such that when downward pressure is exerted, the tip does not move downward or become misaligned with the instrument. If the tip holder has remained on top of the support structure, it also assists by keeping the tips aligned in their respective holes. The tip holder alone does not provide sufficient support, however, because the tip holder is often a fairly thin and flexible tray that is not a free standing independent support mechanism. A support structure for commercially available tip holders is thus required.
In many settings in which pipette tips are used, it is desirable to minimize the user's handling of the tips. However, most prior art tip mounting systems are not fully satisfactory in this regard primarily because the tips are susceptible to becoming displaced from the tip holder and to requiring manual repositioning in the tip holder or support structure. The tips become inadvertently displaced both when they are initially positioned in the support structure and when they are lifted out of the structure for use.
Most prior art tip mounting systems consist of unwieldy tip releasing or tip loading devices. The tip support structures often have 96 individual holes to which the 96 individual pipette tips have to be aligned. Such precise alignment is extremely difficult to achieve with most existing systems. It is therefore desirable to provide a tip support structure that is easy to use and that minimizes the chance of dislodging the tips and tip holder when placing them in the support structure.
Prior to the present invention, it has been observed that when a user is removing a tip from a tip holder, the tip holder may be inadvertently lifted relative to the support structure so that it requires repositioning before use is resumed. Such inadvertent lifting may occur, for example, when a tip or a row of tips is being removed at an angle other than perpendicular to the tip support. When the tip holder is so lifted, typically the user must handle the system to reposition the tip holder and any displaced tips. It is therefore desirable to provide a pipette tip support structure in which the tip holder resists lifting and dislodging of the tips as the tips are removed.